The present invention relates to a mobile phone. A mobile phone including an antenna arrangement with an antenna element, which is able to radiate in two different radiation patterns, has already been described in German Patent application DE 197 23 331.
The invention proceeds from a mobile phone in accordance is with the generic class of the independent patent claim.
It is already known from the not yet published German patent application DE 197 23 331, that a mobile phone comprises an antenna arrangement with an antenna element which is able to radiate in two different radiation patterns.
It is an object of the present invention to provide an improved mobile phone of the above-described type having a plurality of operation modes, especially a mobile phone which avoids introducing radiation into the head of a user during an active telecommunications connection.
According to the invention the mobile phone has plural operation modes and comprises
an antenna arrangement for propagating radiation in a plurality of different radiation patterns Including at least two radiation patterns that are formed to avoid introducing radiation into a head of a user of the mobile phone when the phone is next to the head during an active telecommunication connection, which antenna arrangement includes one or more antenna elements;
means for assigning at least two of the plural operation modes to a respective different radiation pattern;
means for changing operation between the operation modes; and
means for selecting and activating an assigned radiation pattern selected from the plurality of the different radiation patterns when the corresponding operation mode is active.
The mobile phone according to the invention has the advantage that at least two operation modes of the mobile phone are assigned to a different radiation pattern, respectively, so that during an active operation mode the assigned radiation pattern is selected and activated, and a change between two operation modes causes switching between the assigned radiation patterns. In this way the requirements for the radiation patterns may be adapted to the actual operation mode of the mobile phone. Thereby a compromise may be achieved between the required antenna performance and the amount of radiation In the head of the user depending on the actual operation mode. A more flexible use of the mobile phone is therefore possible.
The features of the dependent patent claims enable further improvement of the invention.
It is very advantageous if only one antenna element is provided in a preferred embodiment of the antenna arrangement to realize at least two different radiation patterns. In this way, the same number of radiation patterns may be realized with fewer antenna elements Therefore, material and costs may be saved as well as weight of the mobile phone.
Another advantage consists in that the antenna arrangement is switchable between an omnidirectional and a directional radiation pattern. Therefore, it is possible to profit from the advantage of an omnidirectional radiation pattern with for example good overall radiation performance as well as from the advantage of a directional radiation pattern with for example a prevention of high radiation in the head of the user according to the requirements defined by the actual or activated operation mode of the mobile phone.
Another advantage consists in that the first radiation pattern is assigned to an idle operation mode during which the mobile phone is not in a telecommunication connection, especially in an on-hook-state, and transmitting control signals, and that second radiation pattern is assigned to a first dedicated operation mode during which the mobile phone is in an active telecommunication connection, especially in an off-hook-state. On this way, a radiation pattern may be chosen for the idle operation mode which allows good overall antenna performance, because in the idle operation mode the mobile phone may be carried inside a jacket or lying on a table and thereby preventing directional radiation. In the dedicated operation mode a directional radiation pattern may be chosen to prevent radiation into the head of the user. Therefore, a good compromise between the performance of the antenna arrangement and the prevention of radiation into the head of the user dependent on the operation mode may be realized.
Another advantage consists in that the third radiation pattern is assigned to a second dedicated operation mode during which the mobile phone is transmitting control signals in an active telecommunication connection, especially in an off-hook-state. On this way, a good overall performance of the antenna arrangement may be chosen in fractions of times when the mobile phone has to transmit control signals to the corresponding base station in an active telecommunication connection state. Thereby, it may be ensured that the control signals reach the corresponding base station without allowing the radiation into the head of the user during the times of the telecommunication connection where no control signals has to be transmitted. This would also represent a good compromise between telecommunication requirements to keep up a telecommunication connection using the transmission of control signals and the reduction of health risk by minimizing the radiation into the head of the user.